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US20090103718A1 - Encryption and decryption methods - Google Patents

Encryption and decryption methods Download PDF

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Publication number
US20090103718A1
US20090103718A1 US12/185,214 US18521408A US2009103718A1 US 20090103718 A1 US20090103718 A1 US 20090103718A1 US 18521408 A US18521408 A US 18521408A US 2009103718 A1 US2009103718 A1 US 2009103718A1
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US
United States
Prior art keywords
block
sentry
encryption
data block
data
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US12/185,214
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English (en)
Inventor
Rui-Hwa Chen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Via Technologies Inc
Original Assignee
Via Technologies Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Via Technologies Inc filed Critical Via Technologies Inc
Assigned to VIA TECHNOLOGIES, INC. reassignment VIA TECHNOLOGIES, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: CHEN, RUI-HWA
Publication of US20090103718A1 publication Critical patent/US20090103718A1/en
Abandoned legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
    • H04L9/06—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols the encryption apparatus using shift registers or memories for block-wise or stream coding, e.g. DES systems or RC4; Hash functions; Pseudorandom sequence generators
    • H04L9/0618—Block ciphers, i.e. encrypting groups of characters of a plain text message using fixed encryption transformation

Definitions

  • the disclosure relates generally to encryption and decryption methods, and, more particularly to methods that encrypt and decrypt data using the content itself.
  • the symmetric encryption/decryption algorithms can be RC4, DES and AES algorithms.
  • a same key is used in data encryption and decryption.
  • the asymmetric encryption/decryption algorithms can be an RSA algorithm.
  • a public key is used in data encryption, and a private key is used in data decryption.
  • a major issue is to make sure the key is securely passed.
  • the asymmetric encryption/decryption algorithm is securer than the symmetric encryption/decryption algorithm; however, it is also complex.
  • FIG. 1 is a schematic diagram illustrating a substitution encryption/decryption algorithm.
  • a letter is substituted by another letter according to the substitution encryption/decryption algorithm to generate a cipher.
  • A is substituted by V
  • B is substituted by G
  • C is substituted by S
  • D is substituted by Q, and the like.
  • the cipher can be cracked in the situation of frequent analysis, so the security is reduced.
  • Encryption and decryption methods are provided.
  • a data block is selected from a plurality of data blocks.
  • a sentry block is determined.
  • the selected data block is encrypting as a cipher text according to the sentry block and the selected data block.
  • a data block is selected from a plurality of data blocks.
  • a sentry block is determined.
  • the selected data block is decrypted as a cipher block according to the sentry block and the selected data block.
  • Encryption and decryption methods may take the form of a program code embodied in a tangible media.
  • the program code When the program code is loaded into and executed by a machine, the machine becomes an apparatus for practicing the disclosed method.
  • FIG. 1 is a schematic diagram illustrating a substitution encryption/decryption algorithm
  • FIG. 2 is a flowchart of an embodiment of an encryption method according to the invention.
  • FIG. 3 is a flowchart of an embodiment of a decryption method according to the invention.
  • FIG. 4A is an encryption example, wherein the number of sentry blocks is 1, and the encryption is an XOR operation performed to the data block;
  • FIG. 4B is a decryption example for the cipher text generated in FIG. 4A ;
  • FIG. 5A is an encryption example, wherein the number of sentry blocks is 2, and the encryption is an XOR operation performed to the data block;
  • FIG. 5B is a decryption example for the cipher text generated in FIG. 5A .
  • Encryption and decryption methods are provided.
  • FIG. 2 is a flowchart of an embodiment of an encryption method according to the invention.
  • data is encrypted using the content itself.
  • step S 210 data is divided into a plurality of data blocks. It is understood that each data block may have the identical length, such as 1 bit, 1 byte, or other size. In some embodiments, the respective data blocks may have different lengths.
  • step S 220 selecting a data block for encrypting.
  • step S 230 determining a sentry block. It is understood that, in some embodiments, the sentry block is a key of other data blocks for encrypting. In some embodiments, the sentry block is the same with the selected data block. In some embodiments, the sentry block is obtained from either a logic operation or an encryption/decryption algorithm of data blocks. In some embodiments, the sentry block is the previous encrypted data block (i.e. a cipher text) which contributes to the complexity of encryption.
  • step S 240 encrypting the selected data block according to the sentry block to obtain a cipher text.
  • the cipher text may be obtained from either a logic operation, such as XOR, AND, OR, and NOT, or an encryption/decryption algorithm, such as a substitution encryption/decryption algorithm, a symmetric encryption/decryption algorithm, or an asymmetric encryption/decryption algorithm of the selected data block and the sentry block.
  • step S 250 determining whether the encryption process is completed. It is noted that, in some embodiments, the encryption process is completed as long as all data blocks of the data are encrypted. In some embodiments, the encryption process is completed while a certain number of the data blocks are encrypted. If the encryption process is completed (Yes in step S 250 ), the procedure ends. If the encryption process is not completed (No in step S 250 ), backs to step 220 . Then, another data block is selected for encrypting.
  • selection and order of the sentry blocks, the selection and order of the data blocks, and related information can be recorded, and can be used as reference in data decryption.
  • FIG. 3 is a flowchart of an embodiment of a decryption method according to the invention.
  • data is decrypted using the content itself
  • step S 310 data is divided into a plurality of data blocks. It is understood that each data block may have the identical length, such as 1 bit, 1 byte, or other size. In some embodiments, the respective data blocks may have different lengths.
  • step S 320 selecting a data block for decrypting.
  • step S 330 determining a sentry block. It is understood that, in some embodiments, the sentry block is a key of other data blocks for encrypting. In some embodiments, the sentry block is the same with the selected data block. In some embodiments, the sentry block is obtained from either a logic operation or an encryption/decryption algorithm of data blocks. In some embodiments, the sentry block is the previous decrypted data block (i.e. a plain text) which contributes to the complexity of decryption.
  • step S 340 decrypting the selected data block according to the sentry block to obtain a plain text.
  • the plain text may be obtained from either a logic operation such as XOR, AND, OR, and NOT, or an encryption/decryption algorithm, such as a substitution encryption/decryption algorithm, a symmetric encryption/decryption algorithm, or an asymmetric encryption/decryption algorithm of the selected data block and the sentry block.
  • step S 350 determining whether the decryption process is completed. It is noted that, in some embodiments, the decryption process is completed as long as all data blocks of the data are decrypted. In some embodiments, the decryption process is completed while a certain numbers of the data blocks are decrypted. If the decryption process is completed (Yes in step S 350 ), the procedure ends. If the decryption process is not completed (No in step S 350 ), backs to step 320 . Then, another data block is selected for decrypting.
  • FIG. 4B is an example for decrypting data blocks as plain texts. Assume performing an XOR operation as encryption. As shown in FIG. 4B , data blocks are Y1, Y2, Y3, . . . , and Yn; and the corresponding plain texts are X1, X2, X3, . . . , and Xn.
  • selecting the data block Y2 for decrypting, and using the previous plain text X1 as the sentry block; therefore, the plain text X2(X2 X1 ⁇ Y2) is obtained.
  • Encryption and decryption may take the form of a program code (i.e., executable instructions) embodied in tangible media, such as products, floppy diskettes, CD-ROMS, hard drives, or any other machine-readable storage medium, wherein, when the program code is loaded into and executed by a machine, such as a computer, the machine thereby becomes an apparatus for practicing the methods.
  • the methods may also be embodied in the form of a program code transmitted over some transmission medium, such as electrical wiring or cabling, through fiber optics, or via any other form of transmission, wherein, when the program code is received and loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the disclosed methods.
  • the program code When implemented on a general-purpose processor, the program code combines with the processor to provide a unique apparatus that operates analogously to application specific logic circuits.

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  • Engineering & Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Storage Device Security (AREA)
US12/185,214 2007-10-17 2008-08-04 Encryption and decryption methods Abandoned US20090103718A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
TW096138823A TWI366371B (en) 2007-10-17 2007-10-17 Encryption and decryption methods
TW96138823 2007-10-17

Publications (1)

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US20090103718A1 true US20090103718A1 (en) 2009-04-23

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US12/185,214 Abandoned US20090103718A1 (en) 2007-10-17 2008-08-04 Encryption and decryption methods

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US (1) US20090103718A1 (zh)
TW (1) TWI366371B (zh)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN118175520A (zh) * 2024-05-11 2024-06-11 合肥工业大学 一种多角度哨兵模式数据采集上传方法及查看方法

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4591660A (en) * 1983-10-25 1986-05-27 At&T Bell Laboratories Common control audio decryptor
US5745577A (en) * 1996-07-25 1998-04-28 Northern Telecom Limited Symmetric cryptographic system for data encryption
US20020141581A1 (en) * 2001-03-29 2002-10-03 Koninklijke Philips Electronics N.V. Methods and apparatus for attacking a screening algorithm
US6711684B1 (en) * 1999-06-08 2004-03-23 General Instrument Corporation Variable security code download for an embedded processor
US6829631B1 (en) * 2000-09-21 2004-12-07 International Business Machines Corporation Method and system for screening electronic messages
US20040255037A1 (en) * 2002-11-27 2004-12-16 Corvari Lawrence J. System and method for authentication and security in a communication system
US20070016641A1 (en) * 2005-07-12 2007-01-18 International Business Machines Corporation Identifying and blocking instant message spam
US20070253549A1 (en) * 2006-04-18 2007-11-01 Ufuk Celikkan Encryption apparatus and method for providing an encrypted file system
US20080232591A1 (en) * 2007-03-21 2008-09-25 International Business Machines Corporation Simple and efficient one-pass authenticated encryption scheme

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4591660A (en) * 1983-10-25 1986-05-27 At&T Bell Laboratories Common control audio decryptor
US5745577A (en) * 1996-07-25 1998-04-28 Northern Telecom Limited Symmetric cryptographic system for data encryption
US6711684B1 (en) * 1999-06-08 2004-03-23 General Instrument Corporation Variable security code download for an embedded processor
US6829631B1 (en) * 2000-09-21 2004-12-07 International Business Machines Corporation Method and system for screening electronic messages
US20020141581A1 (en) * 2001-03-29 2002-10-03 Koninklijke Philips Electronics N.V. Methods and apparatus for attacking a screening algorithm
US20040255037A1 (en) * 2002-11-27 2004-12-16 Corvari Lawrence J. System and method for authentication and security in a communication system
US20070016641A1 (en) * 2005-07-12 2007-01-18 International Business Machines Corporation Identifying and blocking instant message spam
US20070253549A1 (en) * 2006-04-18 2007-11-01 Ufuk Celikkan Encryption apparatus and method for providing an encrypted file system
US20080232591A1 (en) * 2007-03-21 2008-09-25 International Business Machines Corporation Simple and efficient one-pass authenticated encryption scheme

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN118175520A (zh) * 2024-05-11 2024-06-11 合肥工业大学 一种多角度哨兵模式数据采集上传方法及查看方法

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TW200920065A (en) 2009-05-01
TWI366371B (en) 2012-06-11

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Date Code Title Description
AS Assignment

Owner name: VIA TECHNOLOGIES, INC., TAIWAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:CHEN, RUI-HWA;REEL/FRAME:021334/0127

Effective date: 20080723

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION